| Author |
Message |
bobxing
Joined: 23 Jan 2005
Posts: 41
Helped: 1
|
 10 Apr 2006 5:57 What is the difference b/w VOD and VDSAT? |
|
| tags: vdsat mos vdsat mos vdsat hspice vds vdsat |
|
|
In hspice2005.9 and later, for a simple mos transistor simulation, the op has the
calculation of vod=.. and vdsat=.. they might be considerably different.
Anyone can tell their difference?
Thanks in advance.
Bobxing
|
|
| Back to top |
|
 |
bsrivastava
Joined: 09 Sep 2005
Posts: 48
|
| 10 Apr 2006 7:53 Re: What is the difference b/w VOD and VDSAT? |
|
| tags: vdsat vds vdsat |
|
|
Difference of Vds and Vdsat is Vod. Vds-Vdsat = Vod
thanks
-Bharat
|
|
| Back to top |
|
|
bobxing
Joined: 23 Jan 2005
Posts: 41
Helped: 1
|
| 10 Apr 2006 9:05 What is the difference b/w VOD and VDSAT? |
|
| tags: vdsat vds vdsat |
|
|
You give me a good clue. Thanks
I studied the simulated list file.
Vgs-vth=vod,
But Vds-vdsat <> Vod!
so how come? the vdsat?
|
|
| Back to top |
|
|
Material
Joined: 30 Sep 2002
Posts: 34
Helped: 3
|
| 09 Jun 2006 17:16 Re: What is the difference b/w VOD and VDSAT? |
|
| tags: vdsat vds vdsat |
|
|
For long channel device
Vod equal to Vdsat
For short channel device
There existed a lot of second order effects
So Vdsat is not simply equal to Vod
If you want to find out how the hspcie get the vdsat you can refer to the hspice manual, model level.
While in hand calculte we use vod(vgs - vth) instead of Vdsat to simplified the calculation process.
|
|
| Back to top |
|
|
mpig09
Joined: 26 Aug 2005
Posts: 128
Helped: 6
|
| 04 Oct 2008 14:23 Re: What is the difference b/w VOD and VDSAT? |
|
| tags: vdsat mos vdsat mos vdsat hspice vds vdsat |
|
|
Dear all:
Please reference this: http://www.ece.uci.edu/docs/hspice/hspice_2001_2-162.html
If MOS is linear region, vod will closed to vdsat, but when MOS in sat region,
vod will bigger than vdsat.
If you use vod to design you circuit, you will get more margin to ensure the mos in sat region when circuit in different corners and temp.
mpig
|
|
| Back to top |
|
|
